Evaluation of post-radiofrequency myocardial injury by measuring cardiac troponin I levels

The aim of this study was to investigate the extent of myocardial injury created by radiofrequency (RF) ablation. We assessed the changes in levels of cardiac biochemical markers in patients who underwent RF ablation and we sought to evaluate the utility of cardiac troponin I (cTnI) in detecting minor myocardial injury following RF ablation and determine its procedural correlates.

We analyzed the data of 115 consecutive patients who underwent RF ablation. The target sites of RF ablation were slow pathway in 56, left atrioventricular (AV) annulus in 31, right AV annulus in 14, atrial wall in 3, ventricular wall in 6 and AV node in 3 patients. The levels of creatine kinase (CK), CK-MB, cTnI and myoglobin were compared with procedural data and targeted arrhythmia.

Post-RF ablation the concentration of cTnI, CM-MB, CK and myoglobin were significantly different than those of the initial sample. The mean and peak cTnI levels were raised above normal in 63 patients (54.8%). Mean levels of cTnI correlated with the site of RF ablation, being significant for slow pathway ablation, ventricular tachycardia and left AV annulus. We also found a significant association of mean CK-MB, CK levels and left AV annulus.

Our results indicate that radiofrequency ablation results in only minor injury. This marker is effective for detection of RF current induced myocardial injury. Lesions applied to the mitral annulus at the ventricular endocardium are associated with significantly greater myocardial damage.